Ammunition and weapon systems

ABSTRACT

A weapon system employing encapsulated ammunition in which the pressure chamber, located axially rearward of the projectile, is longitudinally or axially offset from but in fluid communication with the propellant capsule chamber. This permits use of ammunition rounds having reduced length for given characteristics of prior rounds, resulting in lightest weight and improved bulk characteristics for the ammunition as well as associated weapon systems. This ammunition concept is adaptable to recoilless, partially recoilless and closed breech ballistic systems in a variety of arrangements.

D United States Patent 1 [1 3,890,878

Grandy June 24, 1975 [54] AMMUNITION AND WEAPON SYSTEMS 2,930,041 3/1960 Massacrier 42/60 1 Inventor Andrew Grand 270? Gram 32132??? 211323 fiiifiiii'iiiij: 1111133158 425? -i North H1118, 19038 3,446,113 5/1969 Dardick 42/395 [22] Filed: Feb. 21, 1974 Primary ExaminerVerl1n R. Pendegrass PP 444,595 Assistant ExaminerC. T. Jordan Related Application Data Attorney, Agent, or Firm-Robert P. Gibson; Nathan [62] Division of Ser. No. 239,595. March 30, 1972, Pat. Edelberg; Somme [57] ABSTRACT [52] US. Cl. 89/1.7 A weapon system employing encapsulated ammuni- [51] Int. Cl. F41F 3/02 tion in which the pressure chamber, located axially [58] Field of Search....89/1.7, 1.704 .705, 155-157, rearward of the projectile, is longitudinally or axially 89/179; 42/17, 39.5, 60, 63 offset from but in fluid communication with the propellant capsule chamber. This permits use of ammuni- [56] References Cited tion rounds having reduced length for given character- UNITED STATES T NT istics of prior rounds, resulting in lightest weight and 217 562 7/1879 improved bulk characteristics for the ammunition as 227:449 5/1880 well as associated weapon systems.

235,2 0 12/1880 This ammunition concept is adaptable to recoilless, 1444949 7/ 1948 partially recoilless and closed breech ballistic systems 2'537443 H1951 in a variety of arrangements. 2,790,353 4/1957 2.817917 l2/1957 6 Claims, 67 Drawing Figures PATENTEIJJUN 24 I975 3, 8 9 O, 8 7 8 SHEET 3 FIG}; FIG.5O FIG.29

JUN24 ms :3 PATENTED SHEET I 5 5. 890 878 PATENTEDJUH 24 I975 SHEET M23 F is. 46

PATENTEDJUH 24 I975 SHEET FIG.59

FIG.55

F|G.6O

AMMUNITION AND WEAPON SYSTEMS The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This is a division of application Ser. No. 239,595, filed Mar. 30, 1972, now US. Pat. No. 3,857,339.

This invention relates to ammunition and weapon systems therefor, and more particularly to a variety of such systems each having the capacity to utilize cartridge capsule ammunition.

Present day cylindrical ammunition does not represent the most efficient, over-all cartridge with respect to bulk and weight.

It is an object of the invention to provide weapon arrangements and cartridge capsule ammunition rounds for use therewith which are of lightness in weight and have improved bulk characteristics.

Another object of the invention is to provide such ammunition and weapon arrangements that can be advantageously used as partially recoilless, fully recoilless or closed breech ballistic systems.

A further object of the invention is to provide such arrangements that can be advantageously used in either fixed projectile or bolt rammed projectile systems.

A further object of the invention is to provide such arrangements that facilitate an improved manner of removing spent ammunition rounds from the firing chamber of the weapon.

A still further object of the invention is to provide means for attaching the cartridges in arrangements that can be advantageously used in single shot, semiautomatic and fully automatic weapons.

Another object of the invention is to provide specific capsule cartridge shapes resulting in efficient packaging arrangements which can be advantageously used in rotary fed and in-line fed single shot, semi-automatic and fully automatic weapons.

A further object of the invention is to provide individual capsule cartridges and multi-cavity, unitized cartridge arrangements which can be advantageously used in rotary fed and in-line fed, single shot, semiautomatic and fully automatic weapons.

These and other objects, features and advantages will become apparent from the following description and accompanying drawings in which:

FIGS. 1-4 are perspective views of a variety of ammunition rounds embodying the principles of the invention.

FIG. 5 is a longitudinal sectional view of the FIG. 1 round.

FIG. 6 is a longitudinal sectional view of a portion of a closed breech weapon system for the FIG. 5 round.

FIG. 7 is a sectional view taken substantially along lines 7-7 of FIG. 6.

FIG. 8 is an exploded view of certain portions of the FIG. 6 arrangement subsequent to firing.

FIGS. 9l3 are views, similar to FIGS. 1-5, ofa modified group of ammunition rounds.

FIG. 14 is a longitudinal sectional view of a portion of a recoilless or partially recoilless weapon system for the FIGS. 9-13 rounds.

FIGS. 15-19 are similar views of a modified group of ammunition rounds.

FIGS. 20 and 21 are longitudinal sectional views of modified portions of weapon systems associated with the rounds of FIGS. 15l9.

FIGS. 22-26 are views, similar to FIGS. l519, of a modified group of ammunition rounds.

FIGS. 27 and 28 are longitudinal sectional views of modified portions of weapon systems associated with the rounds of FIGS. 22-26.

FIGS. 29-32 are perspective views ofa further modified group of rounds.

FIGS. 33 and 34 are perspective views of clusters of capsules of the FIG. 30 and FIG. 32 rounds, respectively.

FIGS. 35 and 36 are perspective views of clusters of capsules of the FIG. 32 and FIG. 31 rounds, respectively.

FIG. 37 is an end view of a modified form of cluster arrangement.

FIG. 38 is a sectional view taken along line 3838 of FIG. 37.

FIG. 39 is a perspective view of a modified cluster arrangement.

FIG. 40 is an exploded perspective view of a linking clip member and ammunition round used in the FIG. 39 arrangement.

FIGS. 41-44 are end views of integral multiple cavity containers of cartridge capsule portions arranged in cylindrical form.

FIG. 45 is a sectional view taken along line 4545 of FIG. 41.

FIG. 46 is a longitudinal sectional view of a portion of a closed breech Weapon system for the FIGS. 41-44 ammunition.

FIG. 47 is a longitudinal sectional view, partially broken away, of multi-cavity container modifications for the FIGS. 41-44 cylinders.

FIG. 48 is a longitudinal sectional view of a portion of a recoilless or partially recoilless weapon system for the FIG. 47 ammunition containers.

FIG. 49 is a view, similar to FIG. 47, of further multicavity container modifications for the FIGS. 41-44 ammunition cylinders.

FIGS. 50 and 51 are longitudinal section views of modified portions of weapon systems associated with the FIG. 49 ammunition containers.

FIG. 52 is a view, similar to FIG. 49, of further multicavity container modifications for the FIGS. 41-44 ammunition cylinders, and FIG. 52A is a partial sectional view taken along line 52A-52A of FIG. 52.

FIGS. 53 and 54 are longitudinal sectional views of modified portions of weapon systems associated with the FIG. 52 ammunition containers.

FIG. 55 is a longitudinal sectional view of a propellant capsule portion of a multi-cavity rectangular prism ammunition cluster.

FIG. 56 is a partial sectional view taken along line 5656 of FIG. 55.

FIG. 57 is a sectional view taken along line 57--57 of FIG. 56.

FIG. 58 is a longitudinal sectional view of a portion of a closed breech weapon system for the FIG. 55 ammunition prisms.

FIGS. 59-61 are views similar to FIG. 55 of modified arrangements.

FIG. 62 is a longitudinal sectional view of a portion of a recoilless or partially recoilless weapon system for the FIG. 59 ammunition prisms.

FIGS. 63 and 64 are longitudinal sectional views of modified portions of weapons systems associated with the FIG. 60 ammunition prisms.

FIGS. 65 and 66 are longitudinal sectional views of modified portions of weapon systems associated with the FIG. 61 ammunition prisms.

The FIG. 1 encapsulated ammunition round shown generally at 101 includes a thin capsule 102 (FIG. of ferrous, non-ferrous or synthetic material of predetermined contour. Preferably ferrous, the cartridge capsule has an elongated substantially cylindrical chamber 103 and a propellant chamber 104 integral therewith but longitudinally offset therefrom. An intermediate necked down metering orifice 105 interconnects or fluidly communicates the propellant chamber 104 with the pressure chamber portion 106 of the cylindrical chamber 103. A projectile 107 is slidably received in the forward barrel portion 108 of chamber 103 in longitudinal alignment with the pressure chamber portion 106. An appropriate percussion primer 109 is secured in a suitably recessed and apertured rear wall portion of the capsule 102., preferably aligned with the propellant chamber 104 which contains the desired granular, flake, sheet or solid grain propellant 110. The transverse sections and end walls 111 of the FIG. 1 round propellant chamber are of substantially rectangular configuration. The embodiments of FIGS. 2, 3, and 4 are of substantially the same construction as the FIG. 1 round, but the transverse sections and corresponding end walls 112, 113, and 114 are of configurations which are substantially square, triangular, and cylindrical, respectively.

The portion of the closed breech weapon system (FIGS. 6-8) includes a substantially cylindrical barrel 120 having an axially offset capsule chamber 121 integral therewith, both the barrel and capsule chamber having a somewhat shortened common wall portion 122 to accommodate the FIG. 1 round prior to firing (FIG. 6) which function is accomplished after the barrel lug 123 and capsule chamber lug 124 are simultaneously engaged by the opposed hook or locking lugs 125, 126 of the rotatable and longitudinally translatable breech means or bolt 127. The closed breech type bolt 127 has a firing pin 128, biased by spring 129 surrounding the firing pin rod or stem 130, with its receptive breech opening 131 in operative alignment with the primer of the round to be fired. The barrel 120 has a transverse opening 102A and an appropriate conduit 120C to direct gas energy for further weapon operation. An ejection rod 134 is slidably mounted in an apertured forward wall 135 of capsule chamber 121 to rearwardly eject a fired or undesired round when the bolt 127 has been rotated out of locking engagement and translated rearward (FIG. 8). The chamber wall 135 is internally recessed to normally seat the ejection rod head 136. The capsule chamber 121 has a crosssection of substantially rectangular configuration to receive the propellant capsule portion of the FIG. 1 round. For firing of the FIGS. 2, 3, or 4 rounds, this transverse section configuration is substantially square, triangular or cylindrical, respectively.

The ammunition rounds of FIGS. 9-13 are distinguished from the FIGS. 1-5 rounds in that the upper cylindrical portion 103A of the thin capsule rearward walls each have a press fitted blow out disc 103C or a pre-formed weakened section as defined by an internal recess 103E (FIG. 13) in the pressure chamber rearward wall portions. The disc or weakened section 103C operatively aligns with recoilless or partially recoilless weapon nozzle 127A (FIG. 14) of the rearwardly enlarging tapered recoil vent 127C provided in the breech or bolt 127. The forward internal surface of the nozzle 127A is formed with a substantially sharp annular edge to facilitate positive shearing action upon the operative portion of the weakened section 103C when sufficient propellant pressure is generated in the pressure chamber portion of cylindrical chamber 103 by the ignited propellant 110.

The ammunition rounds of FIGS. 15-19 contain several variations for their operative firings in the fixed projectile, inserted bolt weapon systems of FIGS. 20 and 21. The capsule cylindrical chamber 203 has an open rearward end 206A adjacent its pressure chamber portion 206, and contains a bottom gas vent 203A which is substantially in vertical alignment with the blow out disc or pre-formed weakened section 204A defined by internal recess 204C in the upper wall of capsule propellant chamber 204. A suitable primer 209 is located in the rearward wall of the propellant chamber which is integrally connected with chamber 203 by the forwardly opening cavity side and rearward walls 205.

In both the FIG. 20 closed breech and FIG. 21 recoilless or partially recoilless weapon systems the common wall portion 222, for the cylindrical barrel 220 and axially offset capsule chamber 221, terminates with a rearwardly extending tongue 222A that fits into the connecting cavity and abuts the cavity rear wall 205 upon loading of the round. Tongue 222A has a vertical gas vent passage 222C that places capsule chambers 203 and 204 in fluid communication upon firing of the round as the developed pressure gas blows out a portion of the weakened section 204A at the sharp edged passage 222C and enters the pressure chamber 206 adjacent the concave recess 227E provided in the forward face of the reduced tip portion 227G on the bolt 227B. The bolt 2278 is longitudinally translatable in the rotational and longitudinally translatable breech member 227. With bolt lug or pin 2271-1 slidable in longitudinal slot 227F of member 227, the bolt is withdrawn rearwardly prior to operative disengagement and engagement of the breech hooking or locking lugs 225, 226 with the barrel lug 223 and capsule chamber lug 224. A recoilless or partially recoilless weapon nozzle 227A (FIG. 21) is provided in bolt 227B at the juncture of the rearwardly enlarging tapered recoil vent 227C and the concave recess 227E.

The ammunition rounds of FIGS. 22-26 are distinguished from the FIGS. 15-19 rounds in that the upper portion of the capsule cylindrical chamber 203 has a lengthwise split or slotted wall 203C. A plurality of camming or dimple means 203E are provided on the internal surface of the pressure chamber portion 206 adjacent the slotted wall 203C and just rearward of projectile 107. This will facilitate the release and barrel chambering of the projectile as the longitudinally translatable bolt 250 (FIGS. 27 and 28) cams the dimple means 203E to spread the inwardly directed substantially annular flange 240 and pushes the projectile to its final pre-firing position in barrel 260. Cylindrical barrel 260 differs from barrel 220 in that an additional intermediate internal recessed surface 261 is provided rearwardly adjacent the rifling 262 to accommodate the forwardmost portion of bolt 250 in its firing position,

while a further recessed surface 263 accommodates the spread portions of split chamber wall 203. The longitudinal slot 271 of the rotational and longitudinally translatable breech member 270 is substantially longer than slot 227F, such that the lug or pin 227H on bolt 250 can be accommodated for its intended full stroke. The forward end of bolt 250 has a forwardly opening nozzle surface 253 that intersects with a concave recess 254 provided on the underside of the bolt, so that the pressure chamber portion 206 fluidly communicates gas vent passage 222C with the rearward end of projecticle 107 in both the FIG. 27 closed breech and FIG. 28 recoilless or partially recoilless weapon systems. The rearwardly enlarging tapered recoil vent 256 (FIG. 28) in bolt 250 intersects concave recess 254 at the effective recoilless nozzle throat 257.

The ammunition rounds of FIGS. 29-32 are each provided with a longitudinally extending groove 104L of dovetail transverse configuration throughout the entire length of a selected propellant capsule chamber wall portion 104, as well as a rib or tongue proturberance 104M of substantially similar dovetail configuration along the length of an opposed longitudinally extending wall portion. Where each substantially similar round has its corresponding tongue and groove surfaces 104M, 104L extending in parallel planes, successive similar cartridge capsules can be integrally linked or connected (FIG. 33, 34) in a substantially straight line cluster pattern. The corresponding dovetailed tongue and groove surfaces of similar rounds can also be formed or oriented in non-parallel planes such that successive similar capsules can be integrally linked or matingly joined to form an arcuate or circular cluster pattern or array (FIGS. 35, 36). Each cluster may be held in an appropriate feeding and stripping mechanism (not shown) which will enable the corresponding breech member to longitudinally translate each stripped round into its weapon position prior to rotational locking motion of the breech member. It is contemplated that each of the previously described rounds (FIGS. 5, 13, 19, and 26) may be so dovetailed for integral linking or connecting purposes, and each fired in their respective weapons which can be slightly altered to accommodate the protruding rib or tongue. The breech locking arrangement on each of the respective weapons also can be relocated to a position somewhat rearward to enable the forward portion of the bolt to have a cross-sectional shape similar or identical to that of the particular cartridge to be chambered.

A modified cluster arrangement (FIG. 37) includes an annular linking member 300 of substantially rearwardly opening U-shaped configuration (FIG. 38) having a plurality of equally spaced arcuate or concave recesses 301 along its peripheral or outermost surface 302 to accommodate an arcuate undersurfce portion of the capsule cylindrical chamber 203 on the FIG. 17 ammunition rounds. The rounds are slid forward onto the metal link ring 300 at each recessed surface 301 such that the ring cradles each round at the rearmost clearance between its propellant chamber 204 and projectile 107 or its supporting cylinder 203. It is contemplated that the ring 300 be formed to cluster similar rounds from any of the groups associated with FIGS. 5, l3, 19 or 26 and that the cluster can be suitably mounted and indexed on weapon system cylindrical stubs of the type to be later described with unitary and radially arranged ammunition containers or clusters.

The modified cluster arrangement (FIG. 39) employs a plurality of individual clip members 330 (FIG. 40) which are shown to be joined or linked by insertion of respective FIG. 1 capsule cartridges 101 into selected substantially C-shaped wings or clip portions of adjacent clips 320. Each link member 320 is formed from a pre-slotted blank or metal member and contains a substantially straight integral or common portion and upper and lower groups of alternately disposed loop portions 321, 322, 323 and 321A, 322A, 323A. The upper loops are formed to enable simultaneous reception of the cartridge capsule cylindrical chamber 103 and projectile 107 by longitudinally spaced loops 323, 321 of one link and intermediate loop 322 of an adjacent link, while the substantially rectangular propellant capsule portion 104 is clipped or received by respective loop portions 323A, 321A or the one link and middle loop 322A of the adjacent link. The substantially straight line type of cluster (FIG. 39) so formed can be used in the same manner as the unitary rectangular ammunition containers or clusters to be later described. Clip members 320 can also cluster separate groups of cartridges of FIGS. 9, 15, 22. The width of the straight common portion of the C-shaped clip portions can be reduced such that similar clips can cluster separate groups of cartridges of FIGS. 2, 10, 16, 23 as well as FIG. 4, 12, 18, 25. The clipping or clustering of separate groups of cartridges of FIGS. 3, ll, 17, 24 can be accomplished where the pre-formed slits of the clip blank are of sufficient length that the lower loops can be bent or inclined to facilitate insertion of the rounds.

The integral or unitary multiple cavity containers 400A, 400B, 400C, 400D (FIGS. 41-44) are preferably made of ferrous, non-ferrous or synthetic material in cylindrical form to contain a cluster of cartridge capsule portions similar to the respective ammunition rounds of FIGS. 1-4. The annular container 400A has a central cylindrical opening 401 (FIGS. 41, 45) and includes a plurality of circumferentially spaced cavities that are defined by integral cartridge capsule portions 402 each having a cylindrical chamber403 and longitudinally offset propellent chamber 404 which is interconnected by metering orifice 405 at the rearmost edge of separating wall 405A. Orifice 405 fluidly communicates the propellant chamber 404 with the pressure chamber portion 406 of chamber 403 whose forward barrel portion 408 slidably receives projectile 107. A suitable primer 409 is secured in an appropriately recessed and apertured rear wall portion of each cartridge capsule portion 402, preferably aligned with propellant chamber 404 that contains the desired propellant 110. An appropriate substantially annular ring shaped end wall closure 411 is suitably secured with cement or the like to seal the forward end of each propellant chamber 404 having a rectangular transverse configuration. Containers 400B, 400C, and 400D will require similar ring end wall closures that suitably seal their respective propellant chambers of substantially square, triangular and cylindrical configurations.

The central opening 401 of each annular container 400A, 400B, 400C, 400D, is slidingly received on the cylindrical stub 402A (FIG. 46) that extends rearwardly from the weapon housing 4208 and parallel to but substantially offset or below the barrel 420 of the closed breech weapon system for the FIGS. 41-44 cy lindrical capsule containers or clusters. Preferably, stub 420A has a tapered rearward end and is centrally located within the rearwardly opening weapon housing annular wall 421 to facilitate the reception of the cylindrical or annular containers that can be delivered by the longitudinally translatable breech means or bolt 427 prior to rotation of the breech to simultaneously secure the opposed hook or locking lugs 425, 426 in engagement with the weapon housing lugs 423, 424. After each successive cartridge capsule portion is suitably indexed to a firing position by means not shown, actuation of spring 429 surrounding the rod or stem 430 of firing pin 428 will initiate the aligned primer 409 to fire the round. When all of the rounds in the cluster or container have been fired, bolt 427 is rotated out of locking engagement and translated rearward to permit the spent container to be replaced by another multicapsule cluster or container.

The multi-cavity ammunition containers of FIG. 47 are distinguished from the FIG. 45 ammunition cylinders in that the rearward walls of each cartridge capsule portion 402 have a blow out disc or pre-formed weakened section 403C as defined by internal recess 403E adjacent the pressure chamber portion 406. Each recess 403E operatively aligns with the recoilless or partially recoilless weapon sharp edged nozzle 427A (FIG. 48) of the rearwardly enlarging tapered recoil vent 427C provided in the breech or bolt 427.

The ammunition containers of FIG. 49, that are fired in the fixed projectile, inserted bolt weapon systems of FIGS. 50 and 51, are distinguished from the FIG. 45 cylindrical clusters in that each cartridge capsule portion 402 has its cylindrical chamber 403 defined by a through bore to provide an open rearward end 406A adjacent its pressure chamber portion 406 for reception of reduced tip portion 427G (FIGS. 50, 51) on the forward end of the bolt 4278 that is longitudinally translatable in the rotational and longitudinally translatable breech member 427. Preferably, a rearward upper wall portion of each capsule propellant chamber 404 is internally recessed at 404C to provide a preformed weakened section or blow-out disc 404A in the full common wall that separates cavities 403 and 404. When each primer 409 is actuated or initiated, developed pressure gas blows out the weakened section or disc 404A and enters pressure chamber 406 adjacent the concave recess 427E provided in the forward face of bolt tip 427G. With bolt pin 427H slidable in longitudinal slot 427F of member 427, the bolt is withdrawn substantially simultaneous with indexing of the associated ammunition cylinder by means not shown, and when a replacement ammunition cylinder is required, bolt withdrawal is followed by operative disengagement and engagement of the breech or locking lugs 425, 426 with the weapon housing lugs 423, 424. A recoilless or partially recoilless Weapon nozzle 427A (FIG. 51) is provided in bolt 427B at the juncture of the rearwardly enlarging tapered recoil vent 427C and the concave recess 427E.

The multi-cavity ammunition containers of FIG. 52 are distinguished from the FIG. 49 ammunition cylinders in that each cartridge capsule portion 402 has the upper portion of its cylindrical chamber 403 provided with a lengthwise split or slotted wall 403$ (FIGS. 52, 52A). A plurality of camming or dimple means 403T are provided on the internal surface of each pressure chamber portion 406 adjacent the slotted wall 4038 just rearward of each projectile 107. This facilitates the release and barrel chambering of the projectile as the longitudinally translatable bolt 450 (FIGS. 53 and 54) earns the dimple means 403T to spread the slotted wall and pushes the projectile to its final pre-firing position in barrel 420. The internal surface of the housing annular wall 421 is of appropriate dimensions the sufficient clearance is provided for lateral spreading of the split cylindrical chambers 403 during the projectile barrel chambering operations. The longitudinal slot 471 of the rotational and longitudinally translatable breech member 470 is substantially longer than slot 427F (FIGS. 50, 51 such that the pin 427H on bolt 450 can be accommodated for the intended full stroke of the bolt. The forward end of bolt 450 has a forwardly opening nozzle surface 453 that intersects with a concave recess 454 provided on the underside of the bolt so that each pressure chamber portion 406 fluidly communicates developed pressure gas from the respective propellant chamber 404 with the rearward end of the corresponding projectile 107 during operation of both the FIG. 53 closed breech and FIG. 54 recoilless or partially recoilless weapon systems. The rearwardly enlarging tapered recoil vent 456 (FIG. 54) in bolt 450 intersects concave recess 454 at the effective recoilless nozzle throat 457.

The unitary or integral multiple cavity ammunition cluster 500 (FIGS. 55-57) is a rectangular prism which is made of materials similar to the aforementioned multi-cavity cylindrical ammunition containers and includes a plurality or cluster of cartridge capsule portions 502 that are integrally arranged in laterally spaced positions across the prism as it is successively moved or fed transversely through the firing chamber 501 (FIG. 58) of a closed breech weapon system having an integral arrangement for the closed breech or bolt and barrel portions 527 and 520, respectively. Each cartridge capsule portion 502 is very similar to the cartridge capsule portions 402 of the FIG. 45 ammunition cylinder. Preferably, a rectangular shaped or elongated cover 511 is cemented to an appropriate receptacle therefor extending across the forwardmost portions of the successively arranged propellant chambers 404. While each of the propellant cavities 404 in the FIG. 55 elongated ammunition prism has been formed with a transverse section of substantially rectangular configuration, the propellant cavities 404 of the rectangular prism may also be of substantially square, triangular and cylindrical configuration, and the end wall closure or seal 51 1 would not require modification.

The type of multi-cavity ammunition prism 500A (FIG. 59) are distinguished from the FIG. 55 ammunition prisms 500 in that the rearward walls of each cartridge capsule portion 502 for each of the prisms provided with a blow out disc or a pre-formed weakened section 503C as defined by internal recess 503E adjacent the pressure chamber portion 406. Each recess 503E operatively aligns with the recoilless or partially recoilless weapon sharp edged nozzle 57A (FIG. 62) of the rearwardly enlarging tapered recoil vent 527C provided in the bolt 527.

The type of ammunition prism 5008 (FIG. 60), that are fired in the fixed projectile, inserted bolt weapon systems of FIGS. 63 and 64, are distinguished from the FIG. 55 ammunition prisms 500 in that each cartridge capsule portion 502 has its cylindrical chamber 403 defined by a through bore to provide an open rearward end 406A adjacent its pressure chamber portion 406 for reception of reduced tip portion 527G (FIGS. 63, 64) on the forward end of the bolt 5278 that is longitudinally translatable in breech portion 527. A rearward upper wall portion of each capsule propellant chamber 404 is internally recessed at 404C to provide a preformed weakened section or blow-out disc 404A in the full common wall that separates cavities 403 and 404. When each primer 409 is actuated or initiated, developed pressure gas blows out the weakened section or disc 404A and enters pressure chamber 406 adjacent the concave recess 527E provided in the forward face of bolt tip 527G. An appropriate pin and slot connection (not shown) between bolt 527B and breech portion 527 enables the bolt to be withdrawn substantially simultaneous with indexing or feeding of the associated ammunition prism through chamber 501 by means not shown. Bolt 5273 is also withdrawn when a replacement ammunition prisms is required. A recoilless or partially recoilless weapon nozzle 527A (FIG. 64) is provided in bolt 527B at the juncture of the rearwardly enlarging tapered recoil vent 527C and the concave recess 527E.

The type of ammunition prism 500C (FIG. 61) are distinguished from the FIG. 60 ammunition prisms in that each cartridge capsule portion 502 has the upper portion of its cylindrical chamber 403 provided with a lengthwise split or slotted wall 403$ and a plurality of camming or dimple means 403T are provided on the internal surface each pressure chamber portion 406 adjacent the slotted wall 403$ just rearward of each projectile 107. This facilitates the release and barrel chambering of the projectile as the longitudinally translatable bolt 550 (FIGS. 65 and 66) cams the dimple means 403T to spread the slotted wall and pushes the projectile to its final pre-firing position in barrel 520. The internal upper surface of the firing chamber 501 is suitably dimensioned that sufficient clearance is provided for spreading of the slotted walls. A suitable pin and substantially long slot connection (not shown) between bolt 550 and breech portion 527 will enable full longitudinal motion of the bolt 550 throughout its intended full stroke. The forward end of bolt 550 has a forwardly opening nozzle surface 553 that intersects with a concave recess 554 provided on the underside of the bolt so that each pressure chamber portion 406 fluidly communicates developed pressure gas from the respective propellant chamber 404 with the rearward end of the corresponding projectile 107 during operation of both the FIG. 65 closed breech and FIG. 66 recoilless or partially recoilless weapon systems. The rearwardly enlarging tapered recoil vent 556 (FIG. 66) in bolt 550 intersects concave recess 554 at the effective recoilless nozzle throat 557.

Various modifications, changes and alterations may be resorted to without departing from the scope of the invention as defined by the appended claims.

I claim:

1. In a weapon system having a substantially cylindrical barrel and breech means rearward of said barrel, said barrel having a longitudinal axis along which a projectile is launchable,

said breech means having a reciprocable firing pin, said firing pin having a longitudinal axis laterally offset from said barrel and barrel axis,

a cylinder housing integral with said barrel and having an internal rearwardly extending substantially central stub, and

said breech means having a recoil vent, said recoil vent being substantially in operative alignment with said barrel.

2. The structure of claim 1 wherein said recoil vent includes a longitudinal passage having a rearwardly enlarging taper.

3. The structure of claim 2 wherein said breech means includes a longitudinally translatable bolt, said bolt having a concave recess provided in its forward face.

4. The structure of claim 3 wherein said recoil vent is in fluid communication with said concave recess.

5. The structure of claim 2 wherein said breech means includes a longitudinally translatable bolt, said bolt having in its forward end a forwardly opening nozzle surface,

said recoil vent being in fluid communication with said nozzle surface.

6. The structure of claim 5 wherein said bolt has a concave recess in a lower portion thereof, said concave recess being in fluid communication with both said recoil vent and said nozzle surface. 

1. In a weapon system having a substantially cylindrical barrel and breech means rearward of said barrel, said barrel having a longitudinal axis along which a projectile is launchable, said breech means having a reciprocable firing pin, said firing pin having a longitudinal axis laterally offset from said barrel and barrel axis, a cylinder housing integral with said barrel and having an iNternal rearwardly extending substantially central stub, and said breech means having a recoil vent, said recoil vent being substantially in operative alignment with said barrel.
 2. The structure of claim 1 wherein said recoil vent includes a longitudinal passage having a rearwardly enlarging taper.
 3. The structure of claim 2 wherein said breech means includes a longitudinally translatable bolt, said bolt having a concave recess provided in its forward face.
 4. The structure of claim 3 wherein said recoil vent is in fluid communication with said concave recess.
 5. The structure of claim 2 wherein said breech means includes a longitudinally translatable bolt, said bolt having in its forward end a forwardly opening nozzle surface, said recoil vent being in fluid communication with said nozzle surface.
 6. The structure of claim 5 wherein said bolt has a concave recess in a lower portion thereof, said concave recess being in fluid communication with both said recoil vent and said nozzle surface. 